s j 
92 Distribution of Timber and the Origin of Prairies. | February, 
slough or stream comes close to the base of the bluffs; the sec- 
ond, when the bluff-side is deeply furrowed with ravines. In the 
former case the slopes are covered with bushes and scrub-oaks, 
often quite to the top. In the latter, the ravines are wooded, — 
usually with the trees extending considerably higher on the j 
south side than upon the north, and often the latter is scarcely 
wooded at all. These points are very evident to one riding over 
the bottom lands so far away as to get a general view. 
(3.) In the low alluvial valleys, the timber is found along the 
streams, usually in narrow strips, widening to fill the bends, and 
usually wider on the east and north sides of the stream. All 
other portions of the bottom lands are remarkably destitute of 
trees and bushes. 
H: 
The timbered areas are very constant, increasing very slowly if 
at all. This is indicated by the existence of old trees, over two hun- 
dred years old, within four or five rods of prairie, and the prairie 
showing no signs of having been previously timbered. Some of 
these cases were on the north side of groves, which side is most — 
exposed to prairie fires, as the north-west wind usually prevails _ 
when the prairies are burning. Moreover after a personal 
acquaintance for the past twenty-five years with numerous locali- 
ties in this region where the annual fires have been kept out, the 
writer has not yet learned of a single case where the advance of 
the timber has been more than five rods, and in the great majority _ 
of cases it has not been as many feet. He has not noted any © 
cases of any destruction of timber by prairie fires except on the 
sand bars, “break offs,” and where freshets break the turf, or 
cover it with a layer of bare earth. From such beginnings som 
times thrifty groves result, but quite as frequently the trees $0 
started barely hold their own against their herbaceous foes, if not 
assisted by the favoring hand of man. In the slow advance of 
groves before alluded to, the Rus glabra takes the front rank, 
_ and the hazel follows, preparing the way for elms, hickories, et 
